Smog levels in Singapore are at their highest recorded level on Wednesday, triggering a run on medical masks.
The National Environment Agency said the index was well past the 200-mark considered as "very unhealthy" and near the "hazardous" level of 301.
According to the NEA website, the index reached 290 at 9pm on Wednesday (local time), surpassing Singapore's previous most severe haze reading in September 1997 when the number peaked at 226.
The ABC reports anything above 200 is considered "very unhealthy" particularly to the elderly, young children and people with heart and lung disease.
The smog has been worsening since Monday and there has been a run on medical masks. Customers and companies are buying them in bulk and placing orders for more.